html table嵌套的问题

Question

如题,怎么使内层table高度和外曾table一样呢
        <table border="1" width=400 height=200>
            <tr height=100%>
                <td>
                    <table border="1" width=100% height=100% >
                        <tr height=100%>
                            <td style="width: 100px">
                            </td>
                            <td>d</td>
                        </tr>
                    </table>
                </td>
            </tr>
        </table>

Answer 1

         <table border="1" width=400 height=200 cellspacing=0 cellpadding=0>
             <tr height=100%> 
                 <td> 
                     <table border="1" width=100% height=100% cellspacing=0 cellpadding=0> 
                         <tr height=100%> 
                             <td style="width: 100px"> 
                             </td> 
                             <td>d </td> 
                         </tr> 
                     </table> 
                 </td> 
             </tr> 
         </table>